Influences of soft prolate spheroid baffle on directivity of acoustic vector sensor

The directivity of vector sensors installed in the sonar dome of underwater vehicles will be distorted by vector sensors´ baffle. This paper selects the soft prolate spheroid as the baffle model. The prolate spheroid baffle is meshed by finite element software, then the mesh is imported into the boundary element software and the directivity of pressure and vibration velocity of diffraction acoustic field are calculated at different frequencies. The results show that under the condition of soft baffle, the pressure is zero on the boundary of the baffle, the phase of diffraction wave and incident wave is reversed and the amplitude of the diffraction wave is equal to the amplitude of incident wave. The symmetry of the directivity of pressure is better in low frequency, but because of the reversed-phase superposition of the diffraction wave and the incident wave, the amplitude of pressure is relatively small. As the frequency increasing, the directivity of pressure is seriously distorted. Because the acoustic energy of diffraction wave mainly concentrates in the radial direction, the radial velocity is seriously distorted by the diffraction wave, on the contrary, horizontal velocity is less distorted.